10 THE STORY OF THE LIVING MACHINE. 



they are distinct from the rest of nature, and there- 

 fore require a distinct origin, it makes little differ- 

 ence whether we looked upon that origin as a sin- 

 gle originating point or as thousands of independ- 

 ent creations. But so soon as it appeared that the 

 present condition of the earth's crust was formed 

 by the action of forces still in existence, and so 

 soon as it appeared that the forces outside of liv- 

 ing forces, including astronomical, physical and 

 chemical forces, are all correlated with each 

 other as parts of the same store of energy, then 

 the problem of the origin of living things as- 

 sumed a new meaning. Living things became 

 then a part of nature, and demanded to be in- 

 cluded in the same general category. The reign 

 of law, which was claiming that all nature's 

 phenomena are the result of natural rather than 

 supernatural powers, demanded some explanation 

 of the origin of living things. Consequently, 

 when Darwin pointed out a possible way in which 

 living phenomena could thus be included in the 

 realm of natural law, science was ready and 

 anxious to receive his explanation. 



Cytology. A third conception which contrib- 

 uted to the formulation of modern biology was 

 derived from the facts discovered in connection 

 with the organic cell and protoplasm. The sig- 

 nificance of these facts we shall notice later, but 

 here we may simply state that these discoveries 

 offered to students simplicity in the place of com- 

 plexity. The doctrine of cells and protoplasm 

 appeared to offer to biologists no longer the com- 

 plicated problems which were associated with ani- 

 mals and plants, but the same problems stripped 

 of all side issues and reduced to their lowest terms. 

 This simplifying of the problems proved to be an 



